At a Glance
Why Get Tested?
To diagnose dengue fever, particularly if you are experiencing fever after travel to a tropical or subtropical destination
When to Get Tested?
When you develop a high fever within 2 weeks of travel to an area where dengue fever is endemic or an outbreak is occurring
A blood sample drawn from a vein in your arm
Test Preparation Needed?
The Test Sample
What is being tested?
Dengue fever is a viral infection transmitted to humans by mosquitoes that live in tropical and subtropical climates and carry the virus. Blood testing detects the dengue virus or antibodies produced in response to dengue infection.
If a person develops a fever within two weeks following travel to an area where dengue fever is present, it may be prudent to test for dengue fever. According to the Centers for Disease Control and Prevention (CDC), dengue infections have been reported in more than 100 countries from parts of Africa, the Americas, the Caribbean, the Eastern Mediterranean, Southeast Asia, and the Western Pacific. It is a fast emerging infectious disease, according to the World Health Organization (WHO), with an increasing number of cases and countries affected throughout the world. Approximately 50 to 100 million cases occur annually worldwide.
In the U.S., the majority of dengue cases occur in travelers returning from areas where dengue is endemic. Most dengue cases in U.S. citizens occur in those inhabitants of Puerto Rico, the U.S. Virgin Islands, Samoa and Guam. Outbreaks where a large number of cases occur in a defined area are rare in the U.S. In recent years, there have been small outbreaks in Texas and Hawaii and a few cases diagnosed in southern Florida.
Many individuals will develop no symptoms at all, or have only a mild illness when exposed to one of the four serotypes of the dengue virus. For those who do develop symptoms, prognosis is still very good for full recovery within a few weeks. The most common initial symptoms are a sudden high fever (104°F or 40°C) and flu-like symptoms that appear roughly 4 to 7 days after being bitten by an infected mosquito (this is called the incubation period and can range from 3 to 14 days). Additional signs and symptoms may include severe headache, especially behind the eyes, muscle and joint pain, skin rash, nausea, vomiting, and swollen glands.
Some people who develop a fever will recover on their own with no lasting ill effects while others may progress to severe dengue fever (sometimes called Dengue Hemorrhagic Fever). If the disease progresses to this form, a new wave of symptoms will appear 3 to 7 days after initial symptoms and as the fever recedes. These may include nose bleeds, vomiting blood, passing blood in the stool, difficulty breathing and cold clammy skin, especially in the extremities. During the second phase, the virus may attack blood vessels (the vascular system), causing capillaries to leak fluid into the space around the lungs (pleural effusion) or into the abdominal cavity (ascites). Currently, there is no explanation as to why dengue fever resolves itself harmlessly in some people while progressing to the severe form in others.
The loss of blood and fluid during the second phase, if untreated, can sometimes develop into a rare condition known as Dengue Shock Syndrome and can be fatal. In order to avoid that complication, a doctor may hospitalize a patient with dengue fever so that falling blood pressure and dehydration caused by the loss of blood and fluids can be managed while the disease runs its course – generally a period of one to two weeks. During the following week of recovery, a person may develop a second rash that lasts a week or more.
Dengue fever is usually diagnosed via some combination of blood tests because the body's immune response to the virus is dynamic and complex. Laboratory tests may include:
- Molecular tests for dengue virus (PCR)—detect the presence of the virus itself; these tests can diagnose dengue fever up to 5 days after the onset of symptoms.
- Antibody tests, IgM and IgG—detect antibodies produced by the immune system when a person has been exposed to the virus; these tests are most effective when performed at least 7-10 days after exposure.
- Complete blood count (CBC)—to look for low platelet count typical of the later stages of the illness and to detect the decrease in hemoglobin, hematocrit, and red blood cell (RBC) count (evidence of anemia) that would occur with blood loss associated with severe dengue fever
- Basic metabolic panel (BMP) – to monitor kidney function and look for evidence of dehydration that can occur with severe illness
How is the sample collected for testing?
A blood sample is collected by inserting a needle into a vein in the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
De Paula, S. and Fonseca, B. (2004). Dengue: a review of the laboratory tests a clinician must know to achieve a correct diagnosis. The Brazilian Journal of Infectious Diseases: an Official Publication of the Brazilian Society of Infectious Diseases. Available online at http://europepmc.org/abstract/MED/15880229 through http://europepmc.org. Accessed June 2013.
Lima, M. et al. (2010). Comparison of three commercially available Dengue NS1 Antigen Capture Assays for acute diagnosis of Dengue in Brazil. PLoS Neglected Tropical Diseases. Available online at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2897844/ through http://www.ncbi.nlm.nih.gov/pmc/. Accessed 5/30/2013.
Rathakrishnan, A., Sekaran, S. (2013). New development in the diagnosis of dengue infections. Expert Opinion on Medical Diagnostics. Available online at http://www.ncbi.nlm.nih.gov/pubmed/23530846 through http://www.ncbi.nlm.nih.gov/pubmed. Accessed 6/1/2013.
Sood, R. (© 2006). Textbook of Medical Laboratory Technology. Jaypee Brothers Publishers. New Dehli, India. Pp 780-787.
World Health Organization. (2009) Dengue Guidelines for Diagnosis, Treatment, Prevention and Control. PDF available for download at http://whqlibdoc.who.int/publications/2009/9789241547871_eng.pdf through http://www.who.int/globalchange/publications/en/. Accessed 5/15/2013.
(October 5, 2010) Centers for Disease Control and Prevention. Dengue. Available online at http://www.cdc.gov/Dengue/ through http://www.cdc.gov. Accessed June 2013.
Cuzzubo A, et al. Use of Recombinant Envelope Proteins for Serological Diagnosis of Dengue Virus Infection in an Immunochromatographic Assay. Clin Vaccine Immunol November 2001 vol. 8 no. 6 1150-1155. Available online at http://cvi.asm.org/content/8/6/1150.full through http://cvi.asm.org. Accessed June 2013.
(September 30, 2011) Mayo Clinic. Dengue Fever. Available online at http://www.mayoclinic.com/health/dengue-fever/DS01028 through http://www.mayoclinic.com. Accessed June 2013.
(January 23, 2013) National Institute of Allergy and Infectious Diseases. Dengue Fever. Available online at http://www.niaid.nih.gov/topics/denguefever/Pages/default.aspx through http://www.niaid.nih.gov. Accessed June 2013.
CDC. 2012 Yellow Book. Dengue Fever & Dengue Hemorrhagic Fever. Available online at http://wwwnc.cdc.gov/travel/yellowbook/2012/chapter-3-infectious-diseases-related-to-travel/dengue-fever-and-dengue-hemorrhagic-fever through http://wwwnc.cdc.gov. Accessed July 2013.
Florida Department of Health. Dengue Fever. Available online at http://www.doh.state.fl.us/environment/medicine/arboviral/Dengue.html through http://www.doh.state.fl.us. Accessed July 2013.